<!DOCTYPE html>
<html lang="en">
<head>
    <style>
	.left {
	    float: left;
	    height: 200px;
	    width: 100px;
	    margin-right: 20px;
	    background-color: red;
	}
	.right {
	    width: 200px;
	    height: 200px;
	    float: right;
	    margin-left: 20px;
	    background-color: blue;
	}	
	.main {
	    height: 200px;
	    overflow: hidden;
	    background-color: green;
	}
    </style>
</head>
<body>
    <div class="container">
        <div class="left"></div>
        <div class="right"></div>
        <div class="main"></div>
    </div>
</body>
</html>